<html>
<head>
<script>
  var count=0;
  function sendMessage() {
    window.parent.postMessage(
      JSON.stringify({"greeting": "hello world"}), // A stringified message to send.
      "*" // The intended origin, in this example we use the any origin wildcard.
    );
  }
  setInterval(function(){
    sendMessage(); // Send a message every second
  },1000);
  
  window.onmessage = function(e){
    if(e.origin === window.location.origin){
      return;
    }
    if(!e.data){
      throw new Error('Message event contains no readable data.');
    }
    console.log(e.data);
    var elm = document.createElement('li');
    elm.innerHTML = e.data;
    var out = document.getElementById('messages');
    out.appendChild(elm);
  }
</script>
</head>
<body>
  <p>child window on different domain <a href="https://gist.github.com/kylewelsby/585b3a5395c6731acc50">GitHub Gist</a></p>
  <ol id="messages"></ol>
</body>
</html>
